US 5,492,001 AGranted

Method and apparatus for working burred portion of workpiece

AssigneeYutaka Giken Co., Ltd.

InventorsZirou Sasaki, Masuhiro Yamamoto, Norio Gotoh

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Abstract

The periphery of a workpiece which has already been subjected to burring is at least partially punched by a periphery punch and a periphery die. The burred portion is then further pressed by the periphery punch and a die surface including an annular portion which opposes the periphery punch while restricting the lateral movement of the workpiece by the periphery die. An apparatus for working a burred portion is made up of a metallic mold having a periphery die and a periphery punch, a lifter which is disposed inside the periphery die so as to be movable up and down relative to the periphery die, and further working device for further working the burred portion into a shape and dimension of those of a final product of the workpiece. The further working device includes a pilot pin which is projectingly fixed to a lower end of the periphery punch and a knockout which is disposed in a recess in the lifter and which has an annular portion on its upper edge.

Claims25

Dependent claims

A method of shaping a burred portion of a metallic plate, comprising the steps of:

providing a metallic plate having a generally flat upper surface and a central opening within the plate, the central opening having a burred portion therearound and extending transverse to the generally flat upper surface, and the burred portion having a rounded edge (3) at a base of the burred portion which connects to the flat upper surface;
providing a periphery die which has an inside annular surface which is sized to surround a portion of said metallic plate at a location outside and surrounding said central opening;
providing a punch having a surface adapted to contact the generally flat upper surface;
providing a lifter having a surface adapted to contact a generally flat lower surface of the metallic plate which extends from the outside of the burred portion to the periphery die;
providing a knockout having a ring portion having a generally flat surface adapted to contact a front end (4) of the burred portion;
providing a central member (13, 38) having an outer annular surface adapted to fit inside the central opening and to contact an inside surface of the burred portion;
pressing the metallic plate between the punch and the lifter, while the ring portion of the knockout contacts the front end of the burred portion, the outer annular surface of the central member contacts the inside surface of the burred portion, and the inside annular surface of the periphery die contacts at least a portion of an outer perimeter of the metallic plate so as to re-shape the plate, while restricting lateral movement of the metallic plate by the pressing of the inside annular surface of the periphery die against the at least a portion of an outer perimeter of the metallic plate.

4 more elements

Dependencies are inferred from the claim text.